New Beginnings and a Secret Crush

After years of marriage and just recently separated, I thought I was ready to move on alone. But fate had different plans when an old friend from college reappeared in my life. We've been catching up over coffee and drinks, and it's like no time has passed since we were young adults flirting across the classroom. Lately, every conversation makes me want more than just friendship, I have a crush on her, but she’s still married. I know that if I act on this, it could ruin everything for both of us, yet seeing her brings out feelings I thought were long gone. What should I do? Is it normal to feel like this after separation?